Measurement of the charge asymmetry in dileptonic decays of top quark pairs in $\mathit{pp}$ collisions at $\sqrt{s}=7$ TeV using the ATLAS detector

A measurement of the top-antitop ($ t\bar{t} $ ) charge asymmetry is presented using data corresponding to an integrated luminosity of 4.6 fb$^{-1}$ of LHC pp collisions at a centreof-mass energy of 7 TeV collected by the ATLAS detector. Events with two charged leptons, at least two jets and large missing transverse momentum are selected. Two observables are studied: $A_{C}^{\ell \ell}$ based on the identified charged leptons, and $A_{C}^{t\bar{t}}$, based on the reconstructed tt final state. The asymmetries are measured to be $A_{C}^{\ell \ell} =0.024\pm 0.015\left ( stat. \right )\pm 0.009\left ( syst. \right ), A_{C}^{t\bar{t}} =0.021\pm 0.025\left ( stat. \right )\pm 0.017\left ( syst. \right )$. The measured values are in agreement with the Standard Model predictions.